Fiance Calvert confirmed the news to OK! Magazine, saying "It’s a devastating experience, but all I can do is support Leah and take things day by day. It’s hard, but we will get through it.”

The 19-year-old mother of 2-year-old twin girls Aliannah and Alleah (with ex-husband Corey Simms) suffered the miscarriage at home Saturday, after having extreme pain, bleeding and body aches, a source told the magazine.

The report claim she's "very upset" and "really emotional," but that Calvert, 22, is standing by as her rock. “There have been times during the day when she will just break down and cry,” the insider said of Messer.

Messer and Calvert still plan to get hitched, however. “Leah says that Jeremy definitely is ‘the one’ for her,” the source said, adding, “It’s a sad time for everyone right now, and they are just taking it day by day.”

Meanwhile, the demise of Messer's short-lived marriage to Simms is still playing out on Teen Mom 2, which airs at 10 p.m. Tuesdays on MTV.